This invention relates to electrolytic processing of continuous steel strands.
Coiled steel rod or wire used for forming engine valve spring wire, for example, is typically processed by machining the surface to remove scale and other impurities, producing a relatively smooth finished surface. The machining typically leaves small scratches in the surface of the wire that contribute to failure of the valve springs made from it.
It is known to process coiled steel wire by passing it through an electrolytic cell in which a positive voltage is applied directly to the strand by, e.g., conductive metal rollers, while a negative voltage is applied to an electrode immersed in the electrolyte through which the strand is being passed. The metal rollers may scratch the surface of the metal being processed.
Stricker, U.S. Pat. No. 3,338,809, shows an electrolytic technique for cleaning a continuous strand of steel wire without requiring delivering voltage directly to the strand. In Stricker, the strand is made alternately positive and negative by passing it through a series of electrolytic cells in each of which an electrode is positioned near to but not touching the strand. Assuming that the electrode in a given cell is driven positively, the electrodes in the adjacent cells are driven negatively. The electrodes induce alternately positive and negative voltages on the strand.